1. Field of the Invention
The present invention relates to an imaging optical system evaluation method, an imaging optical system adjustment method, an exposure apparatus and an exposure method, and more particularly relates to the aberration evaluation of an imaging optical system installed in an exposure apparatus.
2. Related Background Art
For example, exposure apparatuses which have built-in projection optical systems for transferring mask patterns onto the resists of wafers are used in lithographic processes that form circuit patterns in the manufacture of LSI. In current lithography, with the increase in the degree of integration of LSI and the compression of the k1 factor (line width=k1×λ/NA; λ indicates the wavelength, and NA indicates the numerical aperture of the projection optical system), there has been a demand for the reduction of the aberration of the projection optical system to the ultimate limit.
Accordingly, in recent years, wavefront aberration has been measured and analyzed using various types of wavefront aberration measuring devices. In the analysis process of wavefront aberration, the measured wavefront aberration is, usually approximated (fitted) using a fringe Zernike polynomial as a function of the pupil coordinates. Here, the Zernike polynomial is a function that expresses the distribution of the wavefront aberration within the pupil.